Science has tricks to see it without risk

Saturday 29 The sun will darken hidden by the moon. It is a partial eclipse that will be visible from an important fraction of the southern hemisphere: almost all of Europe (including Spain) can see this concealment, as can also be seen from part of North America, Africa, Asia and even from a small fraction of South America.

Solar eclipses are astronomical phenomena that hardly go unnoticed. Time has spent since these events ceased to be a sign of evil agüero, but we also know that they have a certain associated risk: the risk of damaging our view If we do not properly protect our eyes.

Looking directly at the sun is never a good idea. But during an eclipse, even less.

As Francisco Doménech and José A. Álvarez explain in The countrythe sun emits its light in a wide segment of the electomagnetic spectrum, a range of frequencies that expands beyond the visible spectrum, entering the infrared and ultraviolet. UVA rays (ultraviolet-a) from which we have to protect ourselves in summer and in certain circumstances are an example of how these invisible rays can still affect ourselves if we do not realize at the time.

The energy transmitted by the different spectrum frequencies is inversely proportional to its wavelength. That is, shorter wave frequencies such as ultraviolet carry more energy than the longest wave, such as infrared. Despite this, both extremes can have a negative impact on the physical integrity of our eye.

What do we expose ourselves? Looking at the eclipse without proper protection can expose permanent damage in the retina and in the cornea. Damages that can even come out with the loss of sight.

According to Geoffrey Bradford, Professor of Pediatrics and Ophthalmology at the University of Virginia Occidental, In an article for The conversationour eyes have a natural capacity to adapt to different luminosity conditions. However, DIRECT OBSERVATION OF THE SUN It can exceed the ability of the eyeball to protect yourself from excess light.

In the cornea, says Bradford, there is a risk of solar or actinic keratosis. This disorder can make our sight cloud and cause pain. This injury would be reversible but may require several days for your cure.

The problems in the retina are not painful but they can be more serious, Bradford adds. Retinopathies can affect our sightcreating a blind spot in our central vision, visual distortions and the alteration of our color perception.

An additional problem is that if we look at the eclipse we will not take pain even though our eyes will be suffering. This can generate a false sense of security while we harm our view.

See it safely

If we want to see the eclipse directly we will need glasses specifically designed for the observation of this type of event. Sun glasses offer protection against solar rays in everyday situations, but eclipses are not such a thing, so in practice their protection of nothing serves us in these situations.

Even if we wear eclipse glasses, we must make sure they are duly approved and comply with the international ISO 12312-2 standard. The National Geographic Institute (IGN) offers us on your website Additional information, including points of sale, to take into account if we want to acquire these glasses.

IGN himself also warns us that we must avoid observing the sun with devices such as cameras, or instruments such as telescopes or prismatic that are not prepared for the observation of these phenomena, something that is only achieved through special filters, not as usually used in other contexts.

If we do not have specialized glasses, we can still observe the eclipse indirectly. If we walk through a wooded zone during the eclipse we can see a curious phenomenon in THE SHADOW THAT PROJECT THE TREES LEAVES. If certain conditions are given, we can see how the shades of the eclipse can be seen among the shadows. Also We can cause this effect Using, for example, the holes of a strainer.

We can, for example, use a Stenopic projector, which we can manufacture ourselves with a cardboard box, aluminum foil, Celoy scissors. NASA explains how In a video.

A last trick that IGN offers us It requires a mirror, a wall and a paper that we must also cut a hole. It is enough to cover the mirror with a role in which we will have previously made a hole between five and ten millimeters in diameter. With it we must reflect sunlight on a flat wall in which the image of the eclipse will be projected.

Saturday’s eclipse is just the appetizer of A complete menu of eclipses that awaits us in the next three years. This eclipses parade includes two total eclipses that in August 2026 and 2027 They will be visible from a good part of the Iberian Peninsula, and an eclipse annular in January 2028 also visible from our environment.

In Xataka | The solar eclipse of March 29 is the starting gun for something historical: Spain will see four eclipses in four years

Image | Jason Howell